Carb - leaky float valve questions

[ako]

Hi. My first thread apart from an into.

Trying to get my 2000 EX250-H running. I bought it in a very un-running condition.

I have renewed the battery charge, engine oil and coolant (all were very low).

I have cleaned the carb components. But the fuel is just flooding through the right bank carb.

So I checked and set the carb floats at 17mm.

Then I tried to check the flow by manually playing with the floats (with the bowls off) and using this supply:



This is the setup:



The right carb was still leaking with the float pressed up. I tried swapping float needles and also rotating them 180 degrees and also 90 degrees.

My main concern is that even swapping the float needles resulted in the right carb leaking. I have ordered 2 new float needles, but hope that the float seat is ok.

Anyone had this problem before? Tried searching but not much luck!

Left float seat:


Right float seat:


Left float:


Right float:


Float needles:

[kkim]

I have, in the past, burnished float valve seats with emery paper. use a long, skinny section or emery paper, wrap it into a skinny tube and push it down into the towers and turn it to try and remove buildup on the seat.

as you already must know, the valve seats are not replaceable (press fitted) and replacing the carbs is the only option if you cannot salvage what you have.

[ako]

Thanks for that tip Kelly. I had only tried cleaning with a cotton bud.

Will get a bit more agressive

[kkim]

Mick,

Yeah, but be very careful not to get too aggressive. Emery cloth/paper is what we used to burnish/electrical communications plugs due to it's very low abrasive qualities. You don't want to distort the brass in that seat, just remove whatever buildup there is from gasoline deposits.

[ako]

I used 1000 grit sand paper which is pretty fine.

Leak gone - brilliant

Thanks for the tip. Now going to check the float level and then put everything back together.....

[kkim]

[ako]

Ok. Now the engine is cranking over.

I have fuel and I have spark (500-550rpm cranking).

Engine not starting. Not even a pop.

I am going to check valve clearance, compression, and timing.

Not sure if there is something else I am missing

[kkim]

the bowls of the carbs need to fill up with gas. on the pregens, this is a relatively difficult thing to do once the carb bowls are emptied. the petcock is vacuum operated and won't flow fuel unless the engine is started. the engine won't start w/o fuel in the bowls.

easiest way is to connect a piece of hose to the vacuum port on the backside of the petcock and gently suck on the hose to create a vacuum. this will allow the fuel to flow down into the carbs. a vacuum gun will work too, if you have one.

some background info on the fuel petcock...
http://faq.ninja250.org/wiki/Rebuild...tcock/fuel_tap

[ako]

I turned the petcock to 'PRI' to fill the bowls up.

I checked the fuel was coming out the bowl drain by opening the bleed screw.

I do have a vacuum gun, and I will check the petcock in the 'ON' position.

[kkim]

sorry, your pregen has a pri position? I thought you had a reserve position? not the same thing.

[ako]

Yeah. ON, RES, and PRI.

Mine is a EX250-H, which is a bit different to the USA bikes.

[kkim]

cool... wasn't aware of that difference. now, I do.

back to your problem...
do you know if the bike was in a running condition when it was last used?

[ako]

The bike blew a hole in a piston. The PO got the pistons replaced but the 'mechanic' couldn't get the bike running again.

I guess the leaky float valve filled the chamber with fuel and the fuel hydro-locked and blew the piston.

The guy didn't have much money and took it too the cheapest mechanic available. I don't think the mechanic had a degree in engine rebuilding

I was hoping I wouldn't need to pull the top end out.

[kkim]

first thing I'd do is a compression check. would save you a lot of time if you knew if the top end was at least able to produce compression.

hydrolocked engines usually bend valves in the process. hope that's not the case, but a compression or leakdown test would be a bit more conclusive.

[ako]

Also forgot to mention the PO has put in the wrong plugs (C7HSA)

I have ordered some CR8HSA plugs, coming in the mail.

I know the current plugs are one heat grade off and the 'R' is for a resistor type plug. But I have a good visible spark. Not sure if this would prevent all ignition though.

Will do a compression test today. I hate taking those spark plugs out without the bendy tool that you are supposed to get with the bike

[kkim]

isn't a 7 one step hotter than the 8? that would concern me, long term, but as far as getting the bike started, it should work for now. just don't do any long rides with them

you could try pouring a small amount of fuel down the spark plug holes to prime the cylinders. about a 1/2 teaspoonful should do it.

"bendy tool"?

our tool kits pretty much look like this...

[ako]

Must have got mixed up about the tool kit. Thought I saw somewhere a flexible spark plug remover.

Anyway, some test results are in. The petcock is working perfectly, a tiny bit of vacuum from the vacuum gun released a torrent of fuel.

The vacuum gauge read 10 inches Hg (5 psi) of vacuum during cranking. That was measured on the hose that opens the petcock. Not sure how much it should be during cranking.

Will do a compression test now both with and without some oil in there to check the rings/valves.

[ako]

Compression fail.

Got 110 psi with oil in. Very low and erratic reading without oil.

Off with her head

[kkim]

Originally Posted by ako

Off with her head

might want to check the valve clearance before popping the head... they might not be closing fully due to being way out of adjustment. if not...

[ako]

Looking for a top end rebuild DIY thread.

Search has got me a valve adjustment (very good details) and an oil change.

Help appreciated.

To drop the engine out of frame or not?

EDIT: Found this link

http://faq.ninja250.org/wiki/What_is..._the_engine%3F

[ako]

Took the cam cover off and found the cam timing was completely off.

This is how it is supposed to be, notice the radial lines with the markings "EX" and "IN":







So I removed the covers from the engine crank and the inspection hole. Note to those that don't live in USA, a AU 50c coin works very well to crack the covers (instead of a nickel I think it is)



Crappy night time photo, but I have highlighted the timing marks in red.



So I turn the engine over until I get the front cam lined up with the head casing, like the illustration above:



And the other cam is almost 180 degrees out of whack. The "IN" marking should be near the RHS of the head casing, but it is actually down the bottom, opposite of the two lines:



Tomorrow I will try to time these correctly, and then take new compression measurements. With any luck this will be my problem

[ako]

Need help working out the timing marks on the flywheel.

I don't have a '1T' or a '2T' marking like this:


I have 3 short dots and a long dash (raised nodes coming out of the flywheel).

The photo in the workshop manual doesn't help much!!!!



I figure if the cams were installed in the wrong orientation, then I should assume that they are also not phased with the crank. So I need to start from scratch.

I can find TDC using a probe into the spark plug hole, but need to get it on the right cycle otherwise my spark will be on the wrong cylinder at the right time.

Any ideas or links?

[kkim]

Mick,

send a PM to Racer X. He's had these engines apart more than anyone here and I'm sure he would be able to help you.

[ako]

PM sent.

A photo of one of the nodes. Not quite aligned with the marker coming down from the inspection hole.

[Racer x]

Hi
There has to be a mark for T2.#2 piston is the piston next to the timing chain. This is a photo of a flywheel with the cover off. The mark is between the two small blocks. There is a long block on the other side of the flywheel. But the make is hard to see. Look way up inside the hole toward the block. Slowly turn the engine around with a rod down the plug hole nearest the cam chain.You will feel the piston come up and stop . it has to be there somewhere.If you really cant find it pull the cover.

I have seen this before with rebuilt engines.The mechanic lines the engine up on #1 and then puts the cam in with IN and EX on the outsides. When you line everything up on # 2 .Both the EX and the IN are then on the inside. AND the engine has low compression and will not start. This will not bend valves because it is exactly 180 deg out of faze.

You will definitely need more than 110psi to get the engine running. Good luck

[Racer x]

The piston #1 piston #2 thing is a bit confusing to people sometimes. Especially car guys. Because on almost all cars the #1 piston is behind the chain. Kawasaki counts there pistons from left to right and if there is a chain it can be anywhere.


This is a good photo of the cam timing . But remember in this view you are looking at the cams from the back side , You are on the left side of the bike looking across the engine. ( just for people that may not realize )

[ako]

Thanks for the help.

I found the 2T mark - it has 'Nippon Japan' stamped over it and it was very hard to see.

The cams are back in and timed with 33 pins.

Will do another compression test tonight and also check the valve clearance.

[ako]

Helps when the valves open and close at the right time.

I now have 170psi in both 1 & 2.

Will add some fuel and spark later on

[ako]

Started up. Purring along.

Bit smokey, hope it's just the oil I tipped into the cylinder.

Thanks to Kelly and Eric for the advice along the way

Still got a bit of work to do, clean her up and fix 1 or 2 broken wires. New spark plugs on the way. New air filter on the way.

Pretty happy though - haven't actually put anything new on her and she runs, so at the moment I have a $500 runner.

Link to original page on YouTube.

[Racer x]

Cool

[kkim]

[CynicalC]

Originally Posted by kkim

easiest way is to connect a piece of hose to the vacuum port on the backside of the petcock and gently suck on the hose to create a vacuum. this will allow the fuel to flow down into the carbs. a vacuum gun will work too, if you have one.

Doesn't apply to him now, but I haven't found this to be needed. I just put my carbs back on today after another cleaning, and adding an inline fuel filter. So the fuel line and float bowls were dry. After putting the tank back on and getting everything hooked back up, the bike fired up in > 10 seconds of cranking.

The bike is a 96 and the tank and petcock are off a later year (2004+ I'd guess based on condition), but still without a "prime" position. The needles are shimmed with 2 washers on each.

BTW This is a very informative thread.

[Racer x]

That is. ZZR 250. I want one of those frames so bad.

[ako]

you want just a frame? or a whole bike?

For racing, as in no need for a title?

[kkim]

Originally Posted by ako

you want just a frame? or a whole bike?

For racing, as in no need for a title?

lol... I can just see the gears turning in people's heads.